The morning news. [volume] (Savannah, Ga.) 1887-1900, 1887-09-08
Sleep-Why We Do It.
From Science.

In an address to the Anthropological So
ciety of Brussels, Prof. Leo Errera has given
a resume of some points in the chemical
theory of sleep. The phenomena of sleep
have, in common with other vital functions,
the character of periodicity. An examina-
ton of such periodic functions in general
may aid in ascertaining the cause of sleep
The respiratory rhythm is regulated by the
amount of oxygen and carbonic acid in the
arterial blood When the blood is charged
with oxygen the respiratory centre momen-
tarily suspends activity; but soon the It's
sues yield their oxygen to the blood, have it
replaced by carbonic acid, and the blood
thus modified acts as an excitant to the
respiratory centre Ranke has shown that
the fatigue and recovery of muscles is
due to similar alienation of the accumu-
lation and discharge of certain 'fatiguinG
substances chief among which is Tactic
acid. An injection of this acid into fresh
muscle renders it incapable of work; wash
ing the acid out restores the activity.
Cannot sleep be explained by a similar
chemical theory? Preyer has extended the
views of Binz, ObeRteiner, and Others who
all agree in making the accumulation of GER
tain products of fatieue--e,mudun0s
the cause of sleep by calling all such fatigu-
ing products of activity ''ponogens. " These
accumulate in waking life, are readily oxi-
dizable, and absorb the oxygen intended for
glands, muscles, and nerve centres until
action is impossible and sleep sets in. Graz
ually the ponogens are destroyed by oxida-
ton, slight excitation is sufficient to aro,ise
the centres, and waking life begins. Among
the ronogens Preyer countlactics acid as the
chief, but the experimental demonstration
of this has been unsuccessful and the theory,
accordingly. not generally adopted.
Since these researches Armand Gautier
has found in the human body series of FIVE
organic bases akin to creatine, creatinine,
and xanthine, and calls them ''leucoinaines'
and 'ptomaines." The physiological prop
critics of these substances are narcotic, ia
tiguing, and sometimes lead to vomiting.
This is just what the chemical theory re
quires. The periodicity of sleep would be
explained by the conservation Of energy
beng applicable to oil bodily activity; work
must be followed by repair; life is slow
suicide. There il, moreover reason to be-
lieve that the action of these leucomaines is
direct one upon the brain; it is q direct
intoxication of the brain centres.
A theory of sleep must take account of
three factors-work, fatigue and sleep. The
chemical theory satisfies these demands All
work, muscular or cerebral, produces waste
products. These accumulate. make work
more and more difficult; this is fatigue As
the process continues, the waste products,
notably the leucomaines, intoxicate the
phine does, and render them incapable of
action; that is sleep. The picture is, how
ever, much more complex. There is a CON
slant struggle against the fatigue which for
time, by diDt of hard work shown in in
creased secretions and so on, may succeed.
We probably never arrive at the extreme
limit of work; the sensation of fatigue
lntervenes to prevent such disaster
Fatigue as is well known, may extend from
mngTln n en-.
centre. We may lee very tired from re-
peatedly lifting q weight, and not be sleepy,
and may be generally sleepy without any
considerable local fatigue One is periphe-
ral the other central As the waste prod
ucts accumulate i'll the centres, motion and
sensation become more and more sluggish,
until the time comes when the ordinary
stimulation no longer arouses them, and VIC
sleep. Partial sleep can be similarly ex-
planned. The centres go TO sleep in hierar-
chlcal order, the highest serving the most
delicate function going first. In waking,
the reverse is the case; the motor centres
may be asleep while the intellectual centres
are awake. In somnambuisn the latter
may be asleep while the former are awake.
The depth of sleep, according to this the
DRY, ought TO be proportional to the mum.
Der OF cortical molecules. in combination
with the leucomaines. In the beginning OF
sleep these are abundant, the cerebral cells
inactive, and a combination easy. The sleer
is deep. Soon the maximum number OF
combinations is reached, and sleep is deep
est. From here on the leucomaines are
gradually eliminated and destroyed, and
sleep should decrease with decreasing in
tensity. Kohlschutter's experiments on the
intensity of sleep. as tested by the noise
necessary to awake the patient, gives the
curve for the intensity of sleep correspond
ing TO what we should expect by our the
DRY. Variations in our sleep, caused by an
excess of work, etc, are evidently similarly
applicable. In short, fatigue is a poison for
which sleep is the normal antidote.
This theory maintains Q) that the activity
of all the tissues land primarily Of the two
most active, the nervous and muscular
gives rise TO substances, more or loss allied
to alkaloids, the leucomaines CT that these
induce fatigue and sleep; % that on waking
If the body is rested, these substances have
disappeared.
To complete the demonstration of these
statements much careful experimentation is
necessary; but the facts as far as they &C
make il probable that the chemical theory
Of sleep will gain in strength with our
knowledge.